Well testing device



.ne 6, 1939. F. E. 'o'NElLL WELL TESTING DEVICE Filed May 17. 1937 m n Nmy l JMA/fok @i @a W Patented June 6, 1939 PATENT OFFICE WELL TESTINGDEVICE Frank E. ONeill, Glendale, Calif., assignor to Mordica 0.Johnston, Glendale, Calif.

vApplication May 17, 1937, SerialNo. 143,022

` 4 Claims.

This invention relates to testing apparatus, and particularly pertainsto a well testing device.

In the drilling of oil wells it has been found desirabie to ascertainthe fluid pressure existing in the formation at a desired depth, andparticularly in that portion of the well known as the rathole. Due tothe fact that it is usual to maintain the well filled with drillingfluid during the testing operation, it is necessary that the column of mfluid above the are'a to be tested shall be packed oil so that theshut-in pressure of the native fluids in the formation can be measured.It is therefore necessary to provide some means, such as a packer, bywhich the upper column of fluid inthe well may be sealed off from thezone to be tested. It is also common practice in making these tests toform a reduced bore at the lower end of the main bore which has beendrilled. This reduced bore is commonly called a rat-hole and it iswithin this bore that a perforated anchor pipe is placed carrying thepressurlrecording means with which a test is made. It is obvious thatwhen the perforated anchor pipe carrying a packer ls loweredv into therat-hole and a flow of fluid is permitted to ente'r the perforated pipeand to pass upwardly through the .drill string by which `the structureis supported, that there is a tendency for the formation to cave so that4the debris and heavy mud at the bottom of the hole will tend to clogthe perforations at the lower end of the anchor pipe, and through whichthe fluid pressure of which is to be measured passes. Thus it will beevident that the fluid which passes vthrough the-perforations to thepressure recording means will be restricted in its ilow so that anaccurate recording would not be obtained. It will also be evident thatin .the event the formation caves in around the perforated anchor pipeand the pressure bomb the pressure bomb might be lost in the hole. It isthe principal object of the present invention therefor to provide astructure by which fluid pressure tests may' be made in a well and inwhich structure the pressure responsive means is so positioned as toinsure that its reading will be a direct and accurate index of the truepressure in the formation, and that the pressure responsive means willbe so positioned as to be protected from caving formation and to bereadily removed from the well even though the anchor pipe and the packerbecome stuck in the well and have to be disconnected.

The present invention contemplates the pro- Vision of a string of pipeto be lowered into a well at the lower end of which is carried a valvestructure operable by movement of the string of pipe and beneath whichvalve structure is a cage carrying a fluid pressure recording device,the said cage being mounted above a well packer and a perforated anchorpipe extending downwardly 5 therefrom. I

The invention is illustrated by way of examp in the accompanying drawingin which:

Figure 1 is a view in central vertical section showing a testing deviceembodying the pres- 10 ent invention and disclosing it with itshcontrolvalve opened.

Fig. 2 is a view in central vertical section showing the structure withthe control valve closed.

Fig. 3 is a view drawn at reducedscale and showing a normal method incommon practice at the present time for taking deep well fluid pressurerecordings.

Referring more particularly to the drawing, IIJ indicates a well bore atthe bottom of which a reducedbore II occurs. This last named bore isknown as the rat-hole. Between the rat-hole and the main bore IU is avseat I2 against which and into which a rat-hole packer i3 is forced toform a seal between the main bore I0 above and the rat-hole I I below.It is to be understood that while this invention is described as beingused in connection with a rat-hole packer in an open well bore it is tobe understood that under some circumstances it might be desirable tomake fluid pressure tests in caslngs, at which time a sleeve packer or ahooked-wall packer might be used. The drawing here disclosed will,however, show a suitable application of the invention by way of example.The packer is formed with a central 35 mandrel I4 which is threaded atits lower end and receives a nut I5. Threaded into the mandrel I4 isafperforated anchor pipe I8. Fluid 4from the rat-'hole may flow intothis pipe through the perforations and up through the mandrel III. 40 Abody memberv I'I is threaded to the upper end of the tubular mandrel I4and the upper end of the body membeais threaded to receive the lower endI8 of housing I9 within which a fluid pressure recording device 20 ismounted. This device may be of any desired commercial design, such forexample, as the structure shown in U. S. Letter's Patent to H. N.Herrick et. al., No. 2,015,851, issued October 1, i935, which structure1s enclosed within a case 2| formed at its lower end with perforatedfluid openings 22. The opposite ends ofthe case are each provided with aconical nose 23. It will thus beI evident that fluid passing through thehousing I9 and around the Vcase 2| will have a stream-lined flow whichwill it will be seen that a valve structure 50 -is pro- 'vided assupported from a drill string 5I.

- cessibility to the pressure bomb 20 the housing I9 may be made in twosections and threaded together as indicated at 25. The upper. end of thehousing I9 is formed with a threaded pin 23 which engages a threadedopening 21 in the lower end of a tubular valve extension 29. The upperend of this extension is internally threaded at 29 to receive a valvepackingmember 30. Carried at the lower end of the member 30 is anannular valve seat 3| against which a tappet valve 32 may seat: Thetappet valve is carried at the lower end of a tubular valve mandrel 33,the upper end of which mandrel is threaded into a sub 34 which isconnected with the lower end of a string of drill pipe 35 by which theentire structure is supe ported and lowered into or'raised from thewell. 'I'he mandrel 33 and the packing element 30 are splined togetheras indicated at 36. An adjusting nut 31 is threaded on to the upperextension of the packing element 30 and provides :a lower seat for avalve spring 38 which is interposed between the nut 31Vand`the lowerface of the sub 34. This valve spring 39 acts to hold the valve 32 onits seat 3I. Fluid openings 39 are radially made through the tubularportion of the valve 32 above its seating face so that iluid. from themember 29 may flow into thevalve and the tubular valve member 33 whenthe valve is opened.

For purposes of emergency circulation a tubular passageway 40 is formedthrough the valve member 32 and is normally closed by a ball valve 4Idisposed at the lower end of the passageway and held in place by spring42. f

In order that the operation, and the advantages of operation, may befully appreciated in the present case, reference is rst made to Fig.

of the 'drawing Where a method of taking pressure tests as commonlypracticed is shown. Here The valve structure carries a packer 52.Extending downwardly from the packer for a desired distance is aperforated anchor v pipe 53 which is iltted with a blind coupling 54:Secured to this coupling'is a'casing 55 having perforationsl 56 adjacentits lower end and within which coupling a ypressure recording device 51is carried. Attention is directed to the fact that in the use of apressure bomb as shown in Fig. 3 the pressure exerted uponl the pressurerecording device is pressure of fluid in a state of quiescence, sincethe fluid only enters the perforations 56 and exerts its pressure uponthe pressure bomb 51, but cannot flow upwardly through the coupling 54since there is no fluid passageway in the coupling which would connectit with the perforated anchor pipe 53. It will thus be seen that undersuch conditions the iiuid from the zone being tested is drawn from thearea above the pressure recording device and there will be a tendency'for magnitude of fluid pressure to be decreased in the zone at thebottom of the well bore which would tend to produce a false reading andwould, at the same time tend to make it possible for the formation tocave in around the member 55 so that the flow of iluid throughthe.passageways tion of pipe 55 carrying the pressurebomb, as well as theenlarged coupling 54 lodged within the hole so that it could not beremoved. Such a condition is decidedly objectionable since pressurerecordingdevices commonly used are quite expensive, as their cost rangesfrom $500 to $1000 each. If the pressure bomb is lost in the hole thereis great difficulty in recovering it by a fishing operation' and it maybe necessary to side track the hole in order to pass it. In any event itwill he evident that with the pressure bomb mounted at a point ofstagnation below the area from which fluid is being withdrawn there isgreat possibility of obtaining an inaccurate fluid pressure test.

Referring now to Figs. 1 and 2 of the drawing the operation of thestructure` embodying the present inventionwlll be explained. When thepressure bomb has been prepared for use it is placed within its housingI9 'and assembled between the packer I3 and the valve structure abovethe packer. The spring 38 maintains the valve closed and the structureis then lowered into the well bore I0 through the accumulated yfluidtherein until the packer I3 seats on the shoulder I2 and the perforatedanchor pipe I6 is extended downwardly into the rat-hole II. The weightof the drill pipe 35 is then imposed upon the packer and will compressthe spring' 38 so that the valve 32 will move away from its seat 3 I. Itwill be understood that since the well is full of'drilling fluid it willexert a hydrostatic pressure at the bottom of the hole in directproportion to the depth of the hole. This pressure roughly amounts toone-half pound per running foot of hole. It will also be seen that asthe packer I3 is forced down into its seat it will tend to increase thepressure in the rat-hole and to at least conne the liquid under apressure substantially represented by the entire fluid column.

When the valve 32 is moved to its opened posi- 7 .tion this pressurewill be relieved and the conflned fluid within the rat-hole will then berelieved to seek a level within the drill string 35 as determinedby thevolume of fluid within the rat-hole and the pressure of this fluid. Thepressure in the rat-hole andr the drill string will thus becomeequalized. After this is accomplished theA weight of the drill string is-relieved while the spring 38 tends to hold the packer on its seat andythus holds the valve seat 3l down so that the valve element 32 may moveupwardly. and rest against it. While the valve 32 is thus resting on itsseat the iluid pressure exerted beneath the packer will be pressure ofthe native fluid within the formation. This is known as the closed-inpressure. As the pressure bomb Yis lowered into the well through thedrilling fluid it will be understood that the pressure responsive meanswill be effected tor indicate progressively the increased pressure dueto the increased hydrostatic head of the fluid column above the pressurerecording device. When the packer is set and before the valve is openedthe pressure responsive means will'rey cord the pressure existing in thearea below the packer. When the valve is opened the pressure below thepacker will be relieved until the column of fluid which rises within thedrill string represents a rhydrostatic head equal to the pressure withindthe rat-hole below the packer. When the valve is then closed and heldclosed for a determined period of time the native fluids within theformation will flow into. the rat-hole and upwardly through theperforated anchor pipe I6 until a maximum closed-in pressure has beenreached. This pressure will be transmitted to the pressure recordingdevice 20 and will thus give an accurate reading showing all of thepressures.

Attention is directed to the fact that since the iiuid which passes intothe lower end of the housing I9 can flow around the pressure lrecordingdevice 20 in an unrestricted stream-line flow the uid pressure which isrecorded will be an accurate indication of conditions as they exist inthe area below the packer. It will also be seen that due to the factthat the fluid may freely flow upwardly around the pressure recordingdevice 20 and thereabove there will not be the possibility for thepressure recording device to be clogged to cause an inaccurate andunreliable pressure reading to be obtained. It is further to be pointedout that since the pressure recording device is disposed above thepacker it is possible to unscrew the housing I9 from the packer in theevent that the packer is lodged in the hole, thus making it possible torecover the expensive pressure recording device 20 with the drillstring, after which an attempt may be made to withdraw the packer by theuse of suitable iishing tools.

l It will thus be seen that by the construction and arrangement of partshere shown, an accurate test may be made of the fiuid pressure occurringwithin the confined area. of a well bore without probability that thepressure recording instrument will become lodged in the well and withthe assurance that the fluid pressure recording will correctly indicatethe pressure conditions prevalent within the confined area, even thoughan accumulation of heavy mud or cavings from the formation will tend toaccumulate around the bottom of the anchor pipe.

While I have shown the preferred form of my invention, as now known tome, it will be understood that various changes might be made in thecombination, construction, and arrangement .of parts, by those skilledin the art, without departing from the spirit of the invention asclaimed.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. A well testing device comprising a packer adapted to be seated withina well bore and having a passageway therethrough, aperforated anchorpipe carried' at the lower end of the packer and communicating with saidpassageway, a. tubular housing connected to the packer and disposedthereabove, said housing having a fluid passageway therethrough incommunication with the packer passageway, pressure recording meansmounted within the fluid housing lowered therein and aroundwhich fluidmay flow as it passes through the housing, a valve structure disposedabove said pressure recording device and controlling the flow of uidthrough the fluid housing, and a string of pipe connected to the valvestructure and 'into which the Valve controlled uid flows.

2. In combination with a packer having a fiuid passageway therethroughand a kvalve structure to control the-flow of fluid, an intermediateunit comprising a tubular housing connecting) the packer and the valvestructure and" providing a fluid passageway therebetween, and a pressurerecording device detachably mounted therein and around which fluid willflow from the packer to the valve structure.

3. In combination with a packer having a fluid passage and a valvestructure to control the ow of fluid therethrough, a tubular housingconnecting between said valve structure and said packer, spider elementsdisposed adjacent the opposite ends of said housing, and a pressurerecording device supported by and between said spider elements andaround which will flow fluid from said packer to said valve structure.

4. An oil well tool comprising a packer adapted to seat in an oil welland create a fluid seal between an area below the packer and an areaabove the packer, a passageway through the packer from the lower area tothe upper area, a tubular CII barrel secured to the upper end of thepacker and the pressure recording device to be removably secured inposition, a string of pipe connected to the upper end of the barrel andthrough which fluid from the barrel may flow, and a valve elementcontrolling the flow of fluid from the upper end of the barrel to thestring of pipe, said valve elementbeing disposed above the pressurerecording means.

. FRANK E. ONEILL.

